Radiofrequency device



Dec. 4 1923.

H. P. DONLE RADIOFREQUENCY DEVICE Filed April 7, 1921 2 Sheets-Sheet 1 IIVVEIVTOR .P 07ZZ6 ATTORNEYS Patented Dec. 4, 1923. a

UNITED STATES PATENT OFFICE.

HAROLD POTTER DONLE, F MERIDEN, CONNECTICUT, ASSIGNOR TO THE CONNECTI- CUT TELEPHONE & ELECTRIC COMPANY, INCORPORATED, OF MERIDEN, CONNECTI- CUT, A CORPORATION OF CONNECTICUT.

RADIOFREQUENCY DEVICE.

Application filed April 7, 1921. Serial No. 459,304.

To all whom it may concern: arranged for observation of the phenomena Be it known that I, HAROLD P. DONLE, a of the tubes operation. citizen of the United States of America, The filament 10 is enclosed in a vacuum 55 residing at Meriden, New Haven County, tube 11 which is surrounded by an anode 12.

Connecticut, have invented a new and use--=-- The coil 13 surrounds the tube and anode ful Radiofrequency Device," of which the and is preferably spaced apart therefrom. following is a specification. The battery 14 supplies current for heat.-

The main object of my invention is to proing the cathode and also for energizing the 00 vide a simple, inexpensive, eflicient, and dumagnet coil 13 and impressing a positive rable means for generating, amplifying, or potential upon the anode. A variable resistdetecting alternating currents, and particuance 15 is employed in the cathode circuit larly those of radio frequencies. Another for modifying the current through the fila-' object is to provide apparatus of this type ment, and a variable resistance 16 is emin which the element which in time becomes ployed in the coil circuit for modifying the- 15 exhausted or depleted is as simple and inexcurrent producing the magnetic field. A

pensive as possible. Another object is to potentiometer 17 is bridged across the batprovide a vacuum tube device which is 1tter for modifying the anode voltage. An self capable of creating radio frequency osinc uctance 18 may be included in the anode cillations, and also one in which the control circuit. Oscillations produced by the de- 20 and selection of the frequency is dependent vice, with or without this inductance 18, upon the constants of the vacuum tube demay be impressed upon another circuit, e. vice itself and which does not depend upon an antenna or other radiating circuit. Te ethe constants of any associated oscillatory phone receivers may be substituted for 18, circuit. a shown in Figs. 5 and 6, and oscillations 25 In its preferred form, the vacuum tube may be impressed upon the tube, either as contains only an axially arranged filamenshown in Fig. 5 or by the absorbing tary cathode. The tube is preferably cylinaction of the tube and the circuits. It drical and provided on its exteriorsurface should be noted that the frequency of the with an anode. A coil surrounds the anode tubes oscillations is substantially independ- 30 and is preferably movable longitudinally of out of the value of this inductance.

the tube. The coil is preferably supplied The glass shield 19 having ventilating with current from the same battery that openings such as 20 is )refei'ably interposed heats the cathode. The tube is preferably between the coil and the tube. 5 surrounded by a shield to prevent fluctua- One end of the filament 10 is supported 35 tions due to changes of temperature. The by a bracket 21. Connection is made to the construction of the tube and coil and the anode by a yoke 22. The tube 11 and the circuit arrangements will be more fully uncircuit terminals for the cathode and anode derstood from the following description and are carried by the base 23 which may also the accompanying dr Wing i be conveniently used as a support for the 40 Fig. 1 is a diagrammatic view of h shield 19. For convenience in mounting the device with a simple form of generating cirtube and its base, I rovide an insulating cuit. member 24 with a soc zet 25. This member Fig. 2 is a side view and partial longitudr 24 may conveniently have a series of circuit nal section of the tube device and coil. t i l 26, 27, 28 d 29, and also have 45 Fig. 3 is an end view of the coil and supsupporting rods 30 and 31 for slidably sup port without the tube. porting the coil. For convenience in mak- Fig. 4 is a side view of a tube with a ing theelectrical connections, I may provide shield in section. spring contacts such as 32 and 33 to which Fig. 5' is a diagrammatic view showing the ends of the coil are connected. These my invention embodied in a receiving circontacts sliding on the rods 30 and 31 maincuit. tain electrical connections as the coil is ad- Fig. 6 is a diagrammatic view of a circuit justed by means of the thumb nut 3a which V tudinally with the cathode.

inductance and capacity. 37 is the companion inductance in circuit with the tube and constituting a secondary inductance coupled to the antenna circuit. This inductance 37 is shunted by a variable condenser 38, the combination forming a reservoir circuit which ma be used to augment the intensit of the osclllations generated by the tube, a though it does not control their frequency. A stopping condenser 39 may also be provided. 40 is a standard high resistance tele-' phone which ma be shunted by a condenser 41. A choke coi 42 may be used or omitted. My device may also be used as a receiver or transmitter without any capacity inductance or turning circuit, in which case I may connect the antennae directly to the anode 12 and ground the negative terminal of the batl ig. 6 shows certain elements in common with Figs. 1 and 5 numbered correspondingly. 43 indicates a meter for indicating the filament current. 44 is a meter for indicating the magnetic field current. 45 is a meter for indicating the anode potential. 46 is a meter for indicating the anode current.

Without intending to be limited, but in order to fully disclose conditions pertinent to my invention, I will now proceed to describe the relative dimensions and electrical condition of apparatus shown in Fig. 6 used in making certain tests for demonstrating the operation of my invention.

The filament was a molybdenum wire .004 of an inch in diameter, in the form of 48 turns wound on a form .02 of an inch in diameter and stretched out to a length of.

1 inch. The approximate length of'the wire in .the filament was 3-} inches. The tube itself was of glass of an external diameter of approximately 9/32 of an inch at the part surrounding the cathode.- The glass was a sodium silicate glass with lime and approximately' 1/32 of an inch thick. The tube was exhausted as completely as possible with commercial apparatus. The anode was in the form of a silver deposit in intimate contact with the glass and co-extensive longi- The coil was formed of No. 24 enameled wire, wound in ten layers, approximately 27/16 inches in length, and with the interior of the coil approximately 1 inch in diameter, making approximately 1150 turns, and with a resistance of 9.8 ohms. The potential of the battery was 6 volts. Throughout the tests the filament nt was .885 amp r 7 With a magnet field current of .405 amperes and the coil arranged over the tube so adjusting nut 34 and moving the coil so as to bring the anode nearer the center of the coil, the anode current was gradually reduced until at a position of the coil one-half: inch lower than shown in Fig. 2, the anode current was approximately 28 microamperes. As the anode approaches the center of the coil the anode current falls off more slowly. It will be obvious that insteadof moving the coil the tube itself might be moved within the coil, since a relative mo tion of the coil and tube is all that is, necessary. The relative movement of the coil and tube as above described resulted not only in a reduction of the anode current, but in an increase in oscillating frequency and a corresponding decrease in wave length; for instance, at the second position of the coil above mentioned, the wave length was approximately 700 meters, corresponding to a frequency of 428,000 cycles per second.

By fixing the coil in position and varying the current through the coil, somewhat similar changes inanode current and oscillation frequency may be produced; for instance, with the same filament current .885 amp. and anode potential 4 volts, and with a coil position intermediate the two above described positions, and with a coil circuit current of .35 amperes, the anode current was 56 microamperes and the wave length was about'880 meters. By increasing the magnetic circuit current to .5 amperes, the anode current fell off to about 19 micro-amperes and the wave length decreased to approximately 650 meters.

The foregoing tests might indicate that the wave length was a direct function of the anode current, but tests in which the filament current, magnetic coil current, andcoil position were held constant and the anode potential was varied, show the contrary. For instance, with the same filament current as before and the same coil position as in the preceding paragraph, and with the magnetic coil current fixed at .405 amperes an anode potential of 3.5 volts produced an anode current of about 24 microamperes. Under these conditions the tube produced oscillations corresponding to a wave length of 780 meters. By increasing the anode potential to 5.5 volts the anode current was increased to approximately 98 microamperes and at the same time the oscillation fre wave length of 715 meters.

not change uniformly with changes in anode potentia Many of the tests which I have made in dicate that with an anode potential above 5.5 volts the particular device described be came more or less unstable. An excessive magnetic field strength is, I believe, detrimental to the operation of the device.

It will be clear, however, that the various constants of the tube will vary with the dimensions and materials employed, and I have given the foregoing figures simplyto illustrate the general construction and mode of operation of the device, without intending to be limited to any particular set of constants.

One of the advantages of the invention is that the device remains sensitive even if the battery employed weakens. This may be due to the interrelation of the elements operating on a common battery under the conditions set forth. I

With the apparatus herein described, as above demonstrated it is possible to obtain continuous oscillations of controllable radio frequencies without the use of a capacity inductance circuit. We are able to alter the period of oscillation by alteration of either the strength or position of the magnetic field or the strength of the electric field between anode and: cathode. It will be seen that the movement of the coil materially affects the frequency at a given filament cur rent. It should also be understood that changes in the temperature of the filament alfect the Wave length.

By the use-of m invention it is possible to utilize a relative y small tube and a minimum volume of metal within the tube in the cathode and its support. As a' result of this small; size, there is a minimum possibility) of gas emanations which are so detrimental to permanent and stable operation of tubes having internal anodes or plates and control elements or grids. It should also be understood that the device may be'used in other circuit arrangements than those herein illustrated, and that I do not consider the broad invention limited to the materials or proportions herein specified.

I claim:

1. In a device of the character described, a vacuum tube, a cathode contained therein, an anode in intimate contact with the outer surface of the tube and connected: to said cathode, and an adjustable magnetizing coil surroundin said anode outside of said tube.

2. In a evice of the character described,

a vacuum tube, a cathode therein, a source of current for said cathode, an anode on the outside of said tube connected to said cathode, and means external of said anode for .pendent of any impressing a magnetic field upon the space within said tube, and means for varying said field independently of the cathode current.

3. ha tube of the character described, a vacuum tube, a cathode contained therein, an anode on the outside of said tubeconnected to said cathode, and means co-acting .With said cathode and said.- anode for generating radio frequency oscillations in said tube, said means being independent of any associated oscillation circuit for controlling the period of oscillation of said tube.

4. In a device of the character described, a vacuum tube, a cathode contained therein an anode on the outside-of said tube, a coil for impressing a magnetic field upon said tube, and a single battery for simultaneously energizing the cathode and said coil.

5. In adevice of the character described,

a vacuum tube, a cathode contained therein, an anode on the outer surface of said tube, a source of direct current for heating said cathode, said anode bein connected to said cathode exteriorly of .sai tube, and an energizing coil in parallel circuit arrangement with said cathode, whereby radio frequency oscillations the frequency of which is indeassociated oscillation circuit are enerated. I g 6. n a device of the character described,

a vacuum tube, a cathode therein extending longitudinally thereof, an anode on the outer surface of said tube co-extensive in length with said cathode and connected thereto, a coil surrounding said anode, and a source of direct current for said cathode, anode and coil whereby the device is inherently productive of oscillations.

7. In a device of the character described, a vacuum tube, a cathodetherein, a non-magnetic anode surroundingsaid tube and connected to said cathode exteriorly of said tube, and means for impressing a controllable magnetic field upon said tube.

8. In a device of the character described, a vacuum tube, a cathode therein, a cylindrical anod'e in intimate contact with the outer surface of said tube and substantially co-extensive with said cathode, and a coil surrounding said tube and said anode and adjustable longitudinally with relation thereto.

9. In a system of the character described, a vacuum tube, a cathode contained therein, an anode surrounding said tube and connected to said cathode, a coil surrounding said anode, a source of current for said cathode and for said coil, and an antenna inductively connected to said anode.

10. In a system of the character described, a vacuum tube, acathode therein, an anode exterior to said tube and connected to said cathode, a translating device-connected to said anode, and means for impressing a ma netic field upon said tube.

11. In a device of the character described,

III

a vacuum tube, a cathode contained therein, a non-magnetic anode on the outside of said tube, a magnetizing coil surrounding said tube, means for supporting said coil, and

means for supporting said tube whereby said tube is removable independently of said coil.

12. In a device of the character described, a vacuum tube, a cathode therein, an anode on the outside of said tube connected exteriorly to said cathode, and a coil surrounding said tube and connected to said cathode.

13. A non-regenerative source of radio frequency oscillations, comprising a vacuum tube, suitable circuits associated therewith, a cathode therein, an anode exterior to said emme tube and connected to the cathode, and means for impressing a magnetic field upon said elements.

14. A non-regenerative source of radio frequency oscillations, comprising a vacuum tube, a cathode therein, an anode exterior to said tube and connected to said cathode,

said tube, and a coil surrounding said anode.

HAROLD POTTER DONLE. 

